Review ArticleSupplementation of hydrogen-rich water improves lipid and glucose metabolism in patients with type 2 diabetes or impaired glucose tolerance
Introduction
The prevalence of type 2 diabetes mellitus (T2DM) has increased worldwide and is becoming a major public health problem in many parts of the world [1]. In Japan, it is estimated that nearly 7 million individuals have T2DM and that another 7 million have a prediabetic condition [2]. Diet and lifestyle are important risk factors in the development of T2DM [3].
Oxidative stress represents an imbalance between the production of reactive oxygen species (ROS) and the activity of antioxidant defense systems [4]. Oxidative stress is recognized widely as being associated with various disorders including diabetes, hypertension, and atherosclerosis. Insulin resistance is now receiving increasing attention, not only as a precursor to T2DM, but also as a predictor of increased risk of cardiovascular disease [5]. It has been reported that antioxidant vitamins such as vitamins C and E have beneficial effects on glycemic control in both humans with T2DM [6], [7] and animal models of diabetes [8], [9]. Shirahata et al [10] reported that electrolyzed-reduced water (ERW), which has a high pH, high dissolved hydrogen, low dissolved oxygen, and extremely negative redox potential values, had the ability to scavenge ROS and therefore protect DNA from oxidative damage. Recently, Kim and Kim reported that administration of ERW improved blood glucose control in animal models of insulin deficiency and insulin resistance [11]. However, an antidiabetic effect of ERW in humans has not yet been demonstrated. More recently, Ohsawa et al reported that hydrogen acts as a therapeutic antioxidant by selectively reducing cytotoxic oxygen radicals [12]. These findings led us to consider the possibility that hydrogen-rich water may be useful as a therapeutic supplement. We recently produced hydrogen-rich pure drinking water by dissolving hydrogen in water purified by the following 3 processes: (1) a reverse osmosis/ultrafiltration, (2) an ion-exchange resin, and (3) an ultrafiltration membrane.
In the present study, to assess whether supplementation with hydrogen-rich pure water had beneficial effects on the progression of diabetes and insulin resistance in humans, we measured lipid and glucose metabolism and several biomarkers of oxidative stress and insulin resistance, including atherogenic lipoproteins and adipocytokines, in patients with either mild T2DM or impaired glucose tolerance (IGT) after consumption of hydrogen-rich water. The study design was a randomized, double-blind, placebo-controlled crossover trial.
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Subjects
The study protocol was approved by the Kyoto Prefectural University of Medicine institutional review board, with informed consent being obtained from all the subjects before enrollment in the study. We recruited 30 patients with T2DM controlled by diet and exercise therapy and 6 patients with IGT (18 men and 18 women; age, 58.6 ± 4.7 years [mean ± SD]; body mass index [BMI], 23.4 ± 3.5 kg/m2 [mean ± SD]), who fulfilled the World Health Organization criteria [13] for diabetes. The patients were
Effect of hydrogen-rich water and placebo water on clinical parameters of glucose and lipid metabolism
The mean levels of lipids/lipoproteins, glucose, insulin, and HbA1c concentrations in the blood at baseline (0 week) and at the end of each water consumption phase (ie, after 8 weeks) are shown in Table 1. Serum emLDL and sdLDL levels were decreased significantly after consumption of hydrogen-rich water (15.5%, P < .01 and 5.7%, P < .05, respectively), but were not altered significantly by consumption of placebo pure water. Intake of hydrogen-rich water tended to decrease oxLDL levels (P =
Discussion
In this study, we demonstrated, for the first time, that consumption of hydrogen-rich pure water for 8 weeks (900 mL/d) in humans resulted in significant reductions in serum modified LDL levels, especially emLDL and u-IsoP. Circulating LDL particles exhibit considerable heterogeneity in density, size, chemical composition, and the electrical charge on the surface of the particle [21]. This difference in electric charge density of LDL particles may influence lipid metabolism. Production of LDL
Acknowledgment
We wish to sincerely thank Hiroshige Itakura (Ibaraki Christian University) for guidance and advice during the study.
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